Louver type led lighting apparatus using dye-sensitized solar cell

ABSTRACT

An LED luminaire has a dye-sensitized solar cell for converting light emitted from a light source to electric energy and uses the converted electric energy. Since the dye-sensitized solar cell plays a role of a louver, the LED luminaire may reflect or shield light and convert wasted light into power. Further, since energy consumption and green-house gas generation decrease, it is possible to provide an environment-friendly LED luminaire Moreover, if the power generated by the dye-sensitized solar cell is used for cooling the LED luminaire, it is possible to enhance heat dissipation efficiency of the LED luminaire

TECHNICAL FIELD

The present disclosure relates to an LED luminaire, and moreparticularly to a louver-type LED luminaire using anenvironment-friendly dye-sensitized solar cell, which has a solar cellfor converting light emitted from a light source to electric energy anduses the converted electric energy.

BACKGROUND ART

The present application claims priority to Korean Patent Application No.10-2010-0124455 filed in the Republic of Korea on Dec. 7, 2010, thedisclosures of which are incorporated herein by reference.

Generally, a light bulb has a short lifecycle, which may further shortendepending on its use time and therefore, may need to be periodicallychecked and exchanged, which will increase maintenance or exchangecosts. However, an LED is advantageous in that it has a lower powerconsumption, semi-permanent lifecycle, rapid response rate, safety andenvironment-friendly property, in comparison to existing light sourcessuch as fluorescent lights and incandescent lights. Therefore, manystudies are being made to replace existing light sources with LEDs,which tend to substitute for general bulbs as a light source of aluminaire such as various kinds of indoor lamps, liquid crystaldisplays, electronic display boards, streetlamps or the like.

Since LED is generally weak against heat generated in operation, mostLED luminaires use various methods for efficient heat dissipation. Forexample, Korean Unexamined Patent Publication No. 10-2009-0130473discloses a power LED module for streetlamps, which emits heat through aheat dissipation plate or the like, and Korean Unexamined PatentPublication No. 10-2009-0095831 discloses a heat diffusion body having aheat diffusion fin or arranged doubly.

However, if natural cooling using a heat dissipation plate or a heatdiffusion fin is applied, the heat dissipation efficiency deterioratesat an LED luminaire which is installed at the ceiling or in a narrowspace. A method for emitting heat by forced cooling using a fan is alsoused in the art. However, this method requires a power source fordriving the fan separately from the power source for the LED andconsumes a lot of power.

Meanwhile, in the case a luminaire is installed at the ceiling or on astand, a louver may be installed in order to limit a radiation angle oflight emitted from the luminaire or prevent the light from causingdazzling to persons out of the radiation angle.

However, if the louver is used for the luminaire, the light blocked bythe louver is wasted.

DISCLOSURE Technical Problem

The present disclosure is designed to solve the problems of the priorart, and therefore the present disclosure is directed to providing anLED luminaire, which may reduce wasted power by using a dye-sensitizedsolar cell as a louver.

The present disclosure is also directed to providing an LED luminaire,which may use a dye-sensitized solar cell as a louver and drive acooling device with power generated by the dye-sensitized solar cell.

The present disclosure is also directed to providing an LED luminaire,which may use the power generated by a dye-sensitized solar cell servingas a louver as a portion of the power used for driving a light emittingunit.

The present disclosure is also directed to providing an LED luminaire,which may reduce energy consumption.

Technical Solution

In one aspect of the present disclosure, there is provided a lightemitting diode (LED) luminaire, which includes a light emitting unithaving at least one LED; a case for accommodating the light emittingunit; and at least one dye-sensitized solar cell installed below thelight emitting unit and dividing a region to which light is irradiatedfrom the light emitting unit.

Preferably, the dye-sensitized solar cell may decrease light emitted ina lateral direction by reflecting light emitted from the light emittingunit and irradiated in the lateral direction.

Preferably, the light emitting unit may be driven by any one of powersapplied from an external power source and the dye-sensitized solar cell.

Preferably, the LED luminaire may further include a fan driven by acurrent generated from the dye-sensitized solar cell and cooling heatgenerated by the operation of the light emitting unit.

Preferably, the dye-sensitized solar cell may include a first glasssubstrate, a second glass substrate and a dye material spread betweenboth glass substrates, and a surface of any one of both glass substrateswhich makes contact with the dye material may be a mirror-surfacereflector.

Advantageous Effects

According to the present disclosure, since a dye-sensitized solar cellplays a role of a louver and converts light, which may be wasted byblocking the light emitted from a luminaire, into electric power, theLED luminaire has very excellent power efficiency.

In addition, since the present disclosure uses the power generatedthrough the dye-sensitized solar cell to drive a cooling device, the LEDluminaire has excellent heat dissipation efficiency and therefore theLED luminaire has long lifecycle and improved reliability.

Moreover, since the present disclosure uses the power generated throughthe dye-sensitized solar cell as a portion of the power for driving alight emitting unit, the LED luminaire has very excellent powerefficiency.

Further, according to the present disclosure, energy consumption andgreen-house gas generation decrease, thereby providing anenvironment-friendly LED luminaire

DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view showing an LED luminaire according to afirst embodiment of the present disclosure.

FIG. 2 is a perspective view showing the LED luminaire according to thefirst embodiment of the present disclosure.

FIG. 3 is a cross-sectional view showing an LED luminaire according to asecond embodiment of the present disclosure.

FIG. 4 is an enlarged view showing a dye-sensitized solar cell of theLED luminaire of FIG. 1 according to the present disclosure.

BEST MODE

It should be understood that the terms used to indicate the direction inthe description and claims which follow, such as ‘upper’ , ‘lower’ ,‘right’ , ‘left’, ‘front’ , and ‘rear’ are relative terms for depictingthe direction viewed on the drawings, and that elements shown in thedrawings are exaggerated, excluded or simplified for the convenience ofunderstanding and clarity. Therefore, the size of each component may notfully reflect an actual size. Also, any explanation of the prior artknown to relate to the present invention may be omitted if it isregarded to render the subject matter of the present invention vague.

<Firs Embodiment>

FIG. 1 is a cross-sectional view showing an LED luminaire 10 accordingto a first embodiment of the present disclosure, and FIG. 2 is aperspective view showing the LED luminaire 10 according to the firstembodiment of the present disclosure.

Referring to FIG. 1, the LED luminaire 10 according to the firstembodiment includes a case 200, a light emitting unit 100, adye-sensitized solar cell 300 and a fan 600.

The case 200 shown in FIG. 1 includes a bottom plate 210, a side plate220 and a top plate 230. The side plate 220 extends downwards from anend of the top plate 230, and the bottom plate 210 is spaced apart fromthe top plate 230 by a predetermined distance and disposed in contactwith the inner side surface of the side plate 220. A space below thebottom plate 210 is called a first accommodation portion 240, and aspace between the bottom plate 210 and the top plate 230 is called asecond accommodation portion 250.

The first accommodation portion 240 accommodates the light emitting unit100. The light emitting unit 100 includes a substrate 110 and at leastone LED element 120 mounted to the substrate 110. The LED element 120 isgenerally arranged regularly as shown in FIG. 2.

The light emitting unit 100 is driven by at least one of powers appliedfrom an external power source and the dye-sensitized solar cell 300. Ifthe light emitting unit 100 has a plurality of LED elements 120, thepower applied from the external power source and the dye-sensitizedsolar cell 300 may be supplied to the plurality of LED elements 120 invarious ways.

For example, the external power source and the dye-sensitized solar cell300 may be connected to the LED element 120 in parallel. In this case, apower source regulator (not shown) is preferably provided at the LEDluminaire 10 to regulate a rated voltage and a rated current used by thelight emitting unit 100 before the power from the external power sourceand the dye-sensitized solar cell 300 is supplied to the light emittingunit 100.

As another example, it is also possible that some LED elements 120(hereinafter, referred to as a group A) is supplied with power only fromthe dye-sensitized solar cell 300, and the other LED elements 120(hereinafter, referred to as a group B) is supplied with power from theexternal power source.

As still another example, the group A may be supplied with power onlyfrom the external power source, and the group B may be supplied withpower from both the external power source and the dye-sensitized solarcell 300.

As further another example, the group A may be supplied with power onlyfrom the dye-sensitized solar cell 300, and the group B may be suppliedwith power from both the external power source and the dye-sensitizedsolar cell 300.

Ratios of the group A and the group B may vary depending on the powerconversion efficiency of the dye-sensitized solar cell 300. In addition,in the case an LED element 120 is capable of being supplied with powerfrom both the external power source and the dye-sensitized solar cell300, a power source regulator for regulating voltage and current of thepower before the power is supplied is preferably provided at the LEDluminaire 10.

In the case the power generated from the dye-sensitized solar cell 300is used by the LED element 120, an amount of external power used may bereduced, which decreases costs of electric energy or the like. Further,green-house gas such as CO₂ generated due to the use of energy is lessdischarged, which realizes an environment-friendly LED luminaire

A surface of the substrate 110 opposite to a mounting surface of the LEDelement 120 comes into contact with the case bottom plate 210. If thebottom plate 210 makes contact with the substrate 110 as describedabove, the heat generated by light emitted by the light emitting unit100 is transferred to the case 200, and the entire case 200 may be usedas a heat diffusion body.

Moreover, a heat diffusion fin 500 is formed at the upper surface of thebottom plate 210. If the heat diffusion fin 500 is formed, the bottomplate 210 makes contact with the air in a larger area, which ensuresmore excellent heat dissipation effect. The heat diffusion fin 500 mayhave any shape as long as it may increase a contact area with the air,without being limited to FIG. 1. In addition, the heat diffusion fin 500may also be formed at the side plate 220 instead of the upper surface ofthe bottom plate 210, and the heat diffusion fin 500 may also be formedat both the bottom plate 210 and the side plate 220.

In order to enhance heat dissipation efficiency, a heat diffusion hole260 is preferably formed at the case 200. Referring to FIGS. 1 and 2,the heat diffusion hole 260 may be formed at the top plate 230 or theside plate 220 and have a slit shape elongated in a horizontal orvertical direction. In addition, the heat diffusion hole 260 may havevarious shapes which help heat dissipation.

The dye-sensitized solar cell 300 is installed below the light emittingunit 100 and divides regions to which light is irradiated from the lightemitting unit 100. Referring to FIGS. 1 and 2, the dye-sensitized solarcell 300 extends downwards from the lower ends of four side plates 220.In addition, a dye-sensitized solar cell 300 for dividing the spacedivided into four dye-sensitized solar cell 300 into a horizontal andvertical lattice is additionally installed.

The louver is a structure which allows the light emitting unit 100 notto be directly watched if the luminaire is observed over a certaindistance, thereby decreasing a radiation angle of light emitted from thelight emitting unit 100. In other words, the louver reflects lightemitted in a lateral direction from the luminaire, not emitted downwardsfrom the luminaire, to decrease the light emitted in the lateraldirection.

In a third embodiment, the dye-sensitized solar cell 300 plays a role ofthe louver. Referring to FIG. 3, an appropriate length of thedye-sensitized solar cell 300 and an appropriate gap between thedye-sensitized solar cells 300 will be described. Here, the lightemitted from the light emitting unit 100 is not directly observed at anangle greater than a louver limit angle θ, thereby preventing dazzling.A shielding angle a is in inverse proportion to the louver limit angleθ. If the louver limit angle θ is great, dazzling is prevented only at alocation far away from the luminaire. If the louver limit angle θ issmall on the contrary, dazzling may be prevented at a location not sofar from the luminaire If the louver limit angle θ is small, the fatigueon the eyes may be reduced but the diffusion range of light decreases,which narrows an area to which light is irradiated. If the louver limitangle θ is great, dazzling increases but light may be irradiated to agreater area. Therefore, the number of dye-sensitized solar cells 300and the vertical length of the dye-sensitized solar cells 300 should besuitably set in consideration of both dazzling prevention and luminaireefficiency. In order to increase the area to which light is irradiatedby the luminaire, the louver limit angle θ should be great. Meanwhile,in order to prevent dazzling by the luminaire, the louver limit angle θshould be small. If the number of dye-sensitized solar cells 300 isgreat, a gap between the dye-sensitized solar cells 300 may be narrow orthe vertical length of the dye-sensitized solar cells 300 may be great.In this case, the louver limit angle θ becomes small.

The dye-sensitized solar cell 300 may reflect the light emitted from theLED luminaire and therefore plays a role of a louver. However, since thedye-sensitized solar cell 300 is transparent, even though thedye-sensitized solar cell 300 plays a role of a louver, thedye-sensitized solar cell 300 does not shield light perfectly but lightmay pass through the dye-sensitized solar cell 300 to some extent.Nevertheless, the light passing through the dye-sensitized solar cell300 is not so strong to cause dazzling. Therefore, the dye-sensitizedsolar cell 300 may fully play a role of a louver which reduces lightemitted in a lateral direction from the LED luminaire.

In the first embodiment, the dye-sensitized solar cell 300 plays notonly a role of a louver but also its inherent role. Therefore, the lightincident to the dye-sensitized solar cell 300 other than light emittedto the outside through the dye-sensitized solar cell 300 and lightreflected on the surface of the dye-sensitized solar cell 300 is usedfor generating power at the dye-sensitized solar cell 300. The powergenerated at the dye-sensitized solar cell 300 is used for driving thefan 600. A wire is connected to an electrode (not shown) formed at thedye-sensitized solar cell 300, and this wire is connected to the fan600, thereby electrically connecting the dye-sensitized solar cell 300to the fan 600.

FIG. 4 is an enlarged view showing a dye-sensitized solar cell of theLED luminaire of FIG. 1 according to the present disclosure.

Referring to FIG. 4, the dye-sensitized solar cell 300 includes a firstglass substrate 310, a second glass substrate 320 and a dye material 330spread between the first and second glass substrates 310, 320. Here,both first and second glass substrates 310, 320 are generally made ofthe same transparent material. However, in case of the first glasssubstrate 310 of the dye-sensitized solar cell, which plays a role of alouver, a surface making contact with the dye material 330 may be formedwith a mirror-surface reflector.

In other words, the light emitted from the light emitting unit passesthrough the second glass substrate 320 and is reflected on themirror-surface reflector of the first glass substrate 310, which allowsthe light to be incident to the dye material 330 to the maximum andtherefor enhances power generation efficiency. Here, in case of thedye-sensitized solar cell 300 shown in a left portion of FIG. 4, thefirst glass substrate 310 having the minor-surface reflector should belocated at the left based on the dye material 330 and the second glasssubstrate 320 should be located at the right. In addition, in case ofthe dye-sensitized solar cell 300 shown in a right portion of FIG. 4,the first glass substrate 310 having the minor-surface reflector shouldbe located at the right based on the dye material 330 and the secondglass substrate 320 should be located at the left.

If the first and second glass substrates 310, 320 are not arranged inthis way, the light emitted from the light emitting unit is reflected onthe minor-surface reflector and not incident to the dye material 330,thereby not generating power by the light.

Here, the mirror-surface reflector is preferably a surface with highreflectivity like a mirror. However, the mirror-surface reflector is notlimited to a mirror-like surface but may include a surface having sosufficient reflectivity to reflect the light emitted from the lightemitting unit 100.

Meanwhile, in case of the dye-sensitized solar cell 300 located in acenter portion of FIG. 4, the first glass substrate 310 having theminor-surface reflector may be located at either the right or the leftbased on the dye material 330.

In other words, every dye-sensitized solar cell 300 should be disposedto receive light emitted from the light emitting unit 100 to generatepower.

Meanwhile, a general dye-sensitized solar cell 300 generates power of407 mV. However, a dye-sensitized solar cell 300′ having theminor-surface reflector generates power of 437 mV. This means that thepower generation efficiency is improved by about 10%. Therefore, sincethe dye-sensitized solar cell 300 plays a role of a louver in thepresent disclosure, the dye-sensitized solar cell 300′ having theminor-surface reflector is more preferred in comparison to a generaldye-sensitized solar cell 300.

Referring to FIG. 1, the fan 600 is formed in the second accommodationportion 250. In more detail, the fan 600 is oriented toward the heatdiffusion fin 500 and installed at the lower surface of the top plate230. However, since the location of the heat diffusion fin 500 may bechanged as described above, the fan 600 may be located at any positionsuitable for blowing wind to the heat diffusion fin 500. For example,the fan 600 may be installed at the inner side surface of the side plate220. In other cases, it is also possible that a driving unit for drivingthe fan 600 is installed out of the case 200 and only blades of the fan600 are located inside the case 200. The air heated while passingthrough the heat diffusion fin 500 or the like is discharged out of theLED luminaire 10 through the heat diffusion hole 260 by the fan 600.

A power source controller (not shown) for driving the LED element 120may be designed to be integrated with the substrate 110. In other cases,the power source controller may be located in the first accommodationportion 240 or the second accommodation portion 250 or installed out ofthe case 200. However, since heat is generated not only from the LEDelement 120 but also from the power source controller, the power sourcecontroller is preferably disposed at a location easily cooled by the fan600.

A storage battery 700 for storing power generated by the dye-sensitizedsolar cell 300 is not provided. However, in the first embodiment, sincethe power generated by the dye-sensitized solar cell 300 is directlyused for the fan 600, the storage battery is not needed. In this case,since the relatively expensive storage battery 700 is not necessary, theproduction cost of the LED luminaire 10 may be lowered.

<Second Embodiment>

FIG. 3 is a cross-sectional view showing an LED luminaire 10 accordingto a second embodiment of the present disclosure. Although the firstembodiment includes the fan 600, the second embodiment does not includethe fan but includes a storage battery 700. If the storage battery 700is provided, there are disadvantages in that the production cost of theLED luminaire 10 increases. However, the advantage is that the powergenerated by the dye-sensitized solar cell 300 may be used at any timeas desired. Except for the above, the configuration of the secondembodiment is substantially identical to that of the first embodiment.

It is also possible to combine the LED luminaire 10 of the firstembodiment and the LED luminaire 10 of the second embodiment. In thiscase, since the storage battery 700 and the fan 600 are providedtogether, it is not necessary to instantly use the power generated bythe dye-sensitized solar cell 300 for the fan 600. Therefore, the fan600 may be operated at any time as desired. For example, it is alsopossible that the power is stored and then used for driving the fan 600during a certain time if the temperature of the substrate 110 or theheat diffusion fin 500 reaches a predetermined level to cool thesubstrate 110 or the heat diffusion fin 500.

Heretofore, a rectangular luminaire installed at the ceiling or the likehas been described in the first and second embodiments. However, thepresent disclosure described based on the embodiments may be identicallyapplied to a circular luminaire or a desk lamp, without being limited tothe above. It would be fully understood that the technical spirit of thepresent disclosure lies in the arrangement and function of thedye-sensitized solar cell 300 and the utilization of power generated bythe dye-sensitized solar cell 300, not in structures of the case 200,the substrate 110, the heat diffusion fin 500 or the like.

In addition, even though the present disclosure has been described basedon embodiments, it should be understood that the detailed descriptionand specific examples, while indicating preferred embodiments of thedisclosure, are given by way of illustration only, since various changesand modifications within the spirit and scope of the disclosure willbecome apparent to those skilled in the art from this detaileddescription. In addition, such changes and modifications should beinterpreted as being included in the range of the present disclosuredefined in the appended claims.

1. A light emitting diode (LED) luminaire, comprising: a light emittingunit having at least one LED; a case for accommodating the lightemitting unit; and at least one dye-sensitized solar cell installedbelow the light emitting unit and dividing a region to which light isirradiated from the light emitting unit.
 2. The LED luminaire accordingto claim 1, wherein the dye-sensitized solar cell decreases lightemitted in a lateral direction by reflecting light emitted from thelight emitting unit and irradiated in the lateral direction.
 3. The LEDluminaire according to claim 1, wherein the light emitting unit isdriven by any one of powers applied from an external power source andthe dye-sensitized solar cell.
 4. The LED luminaire according to claim1, further comprising a fan driven by a current generated from thedye-sensitized solar cell and cooling heat generated by the operation ofthe light emitting unit.
 5. The LED luminaire according to claim 1,wherein the dye-sensitized solar cell includes a first glass substrate,a second glass substrate and a dye material spread between both glasssubstrates, and wherein a surface of any one of both glass substrateswhich makes contact with the dye material is a mirror-surface reflector.6. The LED luminaire according to claim 2, further comprising a fandriven by a current generated from the dye-sensitized solar cell andcooling heat generated by the operation of the light emitting unit. 7.The LED luminaire according to claim 2, wherein the dye-sensitized solarcell includes a first glass substrate, a second glass substrate and adye material spread between both glass substrates, and
 8. The LEDluminaire according to claim 3, further comprising a fan driven by acurrent generated from the dye-sensitized solar cell and cooling heatgenerated by the operation of the light emitting unit.
 9. The LEDluminaire according to claim 3, wherein the dye-sensitized solar cellincludes a first glass substrate, a second glass substrate and a dyematerial spread between both glass substrates, and